The 7850 feeds itself about 150Gb/s. The PS4 is currently spec'd at 176. The GPU has 18 compute units vs. the 7850's 16, will be HSA-compatible, and will routinely have access to 6 or 7GB of VRAM vs. 2. This is aside from the fact that the compute units will probably each be customized and more advanced than the 7850.